 /*******************************************************************************
  * Copyright (c) 2000, 2004 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.test.internal.performance.data;

  
 /**
  * <code>Assert</code> is useful for for embedding runtime sanity checks
  * in code. The static predicate methods all test a condition and throw some
  * type of unchecked exception if the condition does not hold.
  * <p>
  * Assertion failure exceptions, like most runtime exceptions, are
  * thrown when something is misbehaving. Assertion failures are invariably
  * unspecified behavior; consequently, clients should never rely on
  * these being thrown (or not thrown). <b>If you find yourself in the
  * position where you need to catch an assertion failure, you have most
  * certainly written your program incorrectly.</b>
  * </p>
  * <p>
  * Note that an <code>assert</code> statement is slated to be added to the
  * Java language in JDK 1.4, rending this class obsolete.
  * </p>
  */
 public final class Assert {
         
         /**
          * <code>AssertionFailedException</code> is a runtime exception thrown
          * by some of the methods in <code>Assert</code>.
          * <p>
          * This class is not declared public to prevent some misuses; programs that catch
          * or otherwise depend on assertion failures are susceptible to unexpected
          * breakage when assertions in the code are added or removed.
          * </p>
          */
         private static class AssertionFailedException extends RuntimeException {
     
             private static final long serialVersionUID = 1L;

             /**
              * Constructs a new exception.
              */
             public AssertionFailedException() {
                 // empty
 }
             
             /**
              * Constructs a new exception with the given message.
              *
              * @param detail the detailed message
              */
             public AssertionFailedException(String detail) {
                 super(detail);
             }
         }
         
     /* This class is not intended to be instantiated. */
     private Assert() {
         // empty
 }
     
     /**
      * Asserts that an argument is legal. If the given boolean is
      * not <code>true</code>, an <code>IllegalArgumentException</code>
      * is thrown.
      *
      * @param expression the outcome of the check
      * @return <code>true</code> if the check passes (does not return
      * if the check fails)
      * @exception IllegalArgumentException if the legality test failed
      */
     public static boolean isLegal(boolean expression) {
         // succeed as quickly as possible
 if (expression) {
             return true;
         }
         return isLegal(expression, "");//$NON-NLS-1$
 }
     
     /**
      * Asserts that an argument is legal. If the given boolean is
      * not <code>true</code>, an <code>IllegalArgumentException</code>
      * is thrown.
      * The given message is included in that exception, to aid debugging.
      *
      * @param expression the outcome of the check
      * @param message the message to include in the exception
      * @return <code>true</code> if the check passes (does not return
      * if the check fails)
      * @exception IllegalArgumentException if the legality test failed
      */
     public static boolean isLegal(boolean expression, String message) {
         if (!expression)
             throw new IllegalArgumentException ("assertion failed; " + message); //$NON-NLS-1$
 return expression;
     }
     
     /**
      * Asserts that the given object is not <code>null</code>. If this
      * is not the case, some kind of unchecked exception is thrown.
      * <p>
      * As a general rule, parameters passed to API methods must not be
      * <code>null</code> unless <b>explicitly</b> allowed in the method's
      * specification. Similarly, results returned from API methods are never
      * <code>null</code> unless <b>explicitly</b> allowed in the method's
      * specification. Implementations are encouraged to make regular use of
      * <code>Assert.isNotNull</code> to ensure that <code>null</code>
      * parameters are detected as early as possible.
      * </p>
      *
      * @param object the value to test
      */
     public static void isNotNull(Object object) {
         // succeed as quickly as possible
 if (object != null) {
             return;
         }
         isNotNull(object, "");//$NON-NLS-1$
 }
     
     /**
      * Asserts that the given object is not <code>null</code>. If this
      * is not the case, some kind of unchecked exception is thrown.
      * The given message is included in that exception, to aid debugging.
      * <p>
      * As a general rule, parameters passed to API methods must not be
      * <code>null</code> unless <b>explicitly</b> allowed in the method's
      * specification. Similarly, results returned from API methods are never
      * <code>null</code> unless <b>explicitly</b> allowed in the method's
      * specification. Implementations are encouraged to make regular use of
      * <code>Assert.isNotNull</code> to ensure that <code>null</code>
      * parameters are detected as early as possible.
      * </p>
      *
      * @param object the value to test
      * @param message the message to include in the exception
      */
     public static void isNotNull(Object object, String message) {
         if (object == null)
             throw new AssertionFailedException("null argument;" + message);//$NON-NLS-1$
 }
     
     /**
      * Asserts that the given boolean is <code>true</code>. If this
      * is not the case, some kind of unchecked exception is thrown.
      *
      * @param expression the outcome of the check
      * @return <code>true</code> if the check passes (does not return
      * if the check fails)
      */
     public static boolean isTrue(boolean expression) {
         // succeed as quickly as possible
 if (expression) {
             return true;
         }
         return isTrue(expression, "");//$NON-NLS-1$
 }
     
     /**
      * Asserts that the given boolean is <code>true</code>. If this
      * is not the case, some kind of unchecked exception is thrown.
      * The given message is included in that exception, to aid debugging.
      *
      * @param expression the outcome of the check
      * @param message the message to include in the exception
      * @return <code>true</code> if the check passes (does not return
      * if the check fails)
      */
     public static boolean isTrue(boolean expression, String message) {
         if (!expression)
             throw new AssertionFailedException("Assertion failed: "+message);//$NON-NLS-1$
 return expression;
     }
 }

